Undesirable tissue masses such as fibroid tumors are typically dense, tough, and bulky. These characteristics make it difficult to remove a relatively dense tumor using the instruments typically used in minimally invasive endoscopic surgery. Endoscopic tissue graspers and cutters have jaws of limited size and inadequate closing force. Therefore, fibroid tumors are commonly removed by open surgery, which permits direct manipulation and cutting. As a result of the open surgical procedure, the patient experiences a long hospital stay and a long healing and recovery period of six to eight weeks along with a greater risk of infection and a larger area of scarring.
One approach to endoscopically grasping a tumor is through the use of a myoma drill. This drill comprises a rod with a helically shaped distal end for rotatably advancing into the tumor tissue. When positioned in the tumor tissue, the helical drill is used for only manipulating the tissue. A limitation of the drill is that it is only useful as a manipulator. A separate surgical instrument is necessary for cutting the tumor tissue.
One approach to endoscopically removing tissue is through the use of a surgical instrument including a hollow inner tube with a crochet-type hook at the distal end thereof. The instrument also includes an outside cutting sleeve with a rotary cutting edge. The rotary cutting edge turns about the axis of the hollow tube to sweep a portion of the crochet-hook face, thereby cutting an object, such as a suture thread or tissue, that is positioned about the hook for removing sutures and biopsy samples. A problem with this instrument is that the outside cutting sleeve can cut only a small object. The instrument cannot cut a relatively large portion of tissue or systematically debulk a tissue mass such as a fibroid tumor. Furthermore, the crochet-hook of the instrument cannot grasp or stabilize a tumor or a relatively large portion of tissue.
Another approach to endoscopically removing tissue is through the use of a biopsy apparatus including an inner cylinder with a distally positioned corkscrew and an outer barrel with a distally positioned pair of cutting jaws for removing tissue masses such as lesions that are too small to be palpable. When the corkscrew is positioned in tissue, the outer barrel is advanced thereover and the jaws are actuated closed for cutting small bites of soft or fatty tissue. A problem with this apparatus is that the cutting jaws close with an inadequate amount of force. As a result, the apparatus cannot cut tough or fibrous tissue. Furthermore, the action of the jaws serves to push tissue distally away from the jaws so that most of the tissue recedes and only a small bite is cut out of the tissue mass. As a result, the apparatus does not penetrate tissue for debulking a large or dense tumor.